Urine Cortisol: Creatinine Ratio

Lab Section	Clinical Pathology
Test Description	Measurement of urine cortisol and urine creatinine concentrations and calculation of the urine cortisol to creatinine ratio. This test has been utilized as a screening tool for both hyperadrenocorticism and hypoadrenocorticism in dogs.
Species	canine

SUBMISSION DETAILS

Sample Type	1 mL urine
Container	Non-additive blood collection tube or leakproof, unbreakable container
Special Submission Instructions	Refrigerate. Ship with cold packs OVERNIGHT Monday-Thursday.
Turnaround time	1 business day
Interpretation	Urine cortisol to creatinine ratios (UCCR) can be suggestive of either hyperadrenocorticism (if high) or hypoadrenocorticism (if low) but they are NEVER diagnostic of either condition alone. Because the ratio is performed on a single sample that can be collected at home or in clinic, without need for administration of drugs (e.g., ACTH, dexamethasone), it can be a useful and cost-efficient way to direct further investigation. UCCR > 30 may reflect hyperadrenocorticism, stress, or non-adrenal illness. Additional testing (for example, a low dose dexamethasone suppression test) would be required to confirm a diagnosis of hyperadrenocorticism. If clinical suspicion of hyperadrenocorticism is high but UCCR is < 30, additional screening tests are still recommended. A UCCR below this threshold alone does not rule out the possibility of hyperadrenocorticism. If screening a patient for hypoadrenocorticism, a urine cortisol to creatinine ratio >10 strongly suggests hypoadrenocorticism is NOT present. If urine cortisol to creatinine ratio is ≤ 10 in a patient suspected to have hypoadrenocorticism, confirmatory ACTH stimulation testing is recommended.
References	Smiley, L.E. and Peterson, M.E. (1993), Evaluation of a Urine Cortisol:Creatinine Ratio as a Screening Test for Hyperadrenocorticism in Dogs. Journal of Veterinary Internal Medicine, 7: 163-168 Zeugswetter, F., Bydzovsky, N., Kampner, D. and Schwendenwein, I. (2010), Tailored reference limits for urine corticoid:creatinine ratio in dogs to answer distinct clinical questions. Veterinary Record, 167: 997-1001 Moya MV, Refsal KR, Langlois DK. Investigation of the urine cortisol to creatinine ratio for the diagnosis of hypoadrenocorticism in dogs. J Am Vet Med Assoc. 2022 Apr 13;260(9):1041-1047

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